That sort of sounds like a "sorting" process or something like survivor bias. The conditions were more likely to produce pockets of material dense and large eno

That sort of sounds like a "sorting" process or something like survivor bias. The conditions were more likely to produce pockets of material dense and large enough to produce the larger, shorter living stars the earlier back in the universe. i.e. as Time progresses forward the stars which remain are those with more burn time and thus less mass. Otherwise would require some forces to exist which pull mass back together to counter the overall expansion of the universe.